Programmable infusion pumps are used to carry out controlled delivery of liquid food for enteral feeding and medications for various purposes, for example pain management. In a common arrangement, an infusion pump receives a disposable administration set comprising a cassette removably received by the pump and flexible tubing connected to the cassette for providing a fluid delivery path through the pump.
The cassette itself may be intended for use with a particular infusion pump model or models, and/or with tubing having predetermined properties. In this regard, the cassette may include safety features that are designed and manufactured according to specifications determined at least in part by the intended infusion pump model and/or administration set tubing. The safety features of the cassette may cooperate with corresponding features on the matching pump, and may be manufactured according to size tolerances related to tubing diameter and flexibility. For example, the cassette may have an anti-free flow mechanism for protecting the patient from uncontrolled fluid delivery. The anti-free flow mechanism may take the form of an external pinch clip occluder actuated when the cassette is properly loaded in the pump and a door of the pump is closed. Alternatively, the anti-free flow mechanism may take the form of an internal “in-line occluder” that resides within the flow passage of the tubing, wherein a flow passage is only opened when the cassette is properly loaded in the pump and the pump door is closed.
The cassette may provide additional safety features beyond free flow protection. For example, the cassette may be matched to the pump to maintain a desired volumetric accuracy of the pump, and to ensure correct function of occlusion and air-in-line sensors used to trigger safety alarms.
In view of the safety importance of the cassette, it is desirable to provide means to detect whether or not a matching cassette is properly loaded in the pump as a precondition to enabling pump operation.